Conventionally, after forming electrodes on the surface of a varistor element mainly composed of ZnO, a high resistance layer made of glass was formed on the surface of the varistor element, and the surface of the electrodes was plated to obtain a varistor.
However, the high resistance layer made of glass could not be formed selectively on the surface of the varistor element alone, and it was hard to form in a uniform thickness. Accordingly, when plating, plating flow occurred to cause shorting, or moisture invaded into the varistor element to deteriorate the electric characteristic of the varistor.